1. Field of the Invention
The teachings provided herein are generally directed to a system for reducing non-specific binding of an enzyme to lignin to enhance an enzymatic processing of a lignocellulosic material.
2. Description of the Related Art
Enzymatic conversion of a polysaccharide is a useful process for producing chemicals from sustainable resources, and polysaccharides are prevalent in lignocellulosic materials. An efficient utilization of the polysaccharides in a lignocellulosic biomass is desirable, for example, as lignocellulosic biomass is one of the most abundant natural resources on earth. As such, lignocelluloses can be used sustainably to produce biofuel and chemicals, used economically to provide a means of producing materials in developing countries or emerging economies, and used sensibly to mitigate climate change by reducing the reliance on fossil fuels. Currently, however, there is a need to improve the economic viability of these processes, as the state-of-the-art relies on an inefficient use of cellulase enzymes.
Lignocelluloses comprise lignin and polysaccharides: cellulose and hemicellulose. Whereas the polysaccharides can be hydrolyzed into sugars, the lignin is a phenolic polymer that can inhibit an enzymatic saccharification of the polysaccharides. It has been proposed that the inhibition can occur by at least the following problems: (i) a physical blockage problem that limits the ability of the cellulase to access the polysaccharides; and, (ii) a nonspecific adsorption problem, or binding, of the cellulase to lignin. The physical blockage problem can and has been addressed using certain chemical pretreatments that at least partially remove lignin that may block access of the cellulase to the cellulose, but the lignin content is often enriched relative to the polysaccharides due to the simultaneous removal of hemicelluloses during chemical pretreatment. As a result, the problem of nonspecific adsorption (or binding) of cellulase enzymes to lignin is not addressed and, moreover, can be exacerbated.
One of skill would appreciate a way of reducing the enzyme dosages required to achieve a desired level of saccharification, and reducing the nonspecific binding of the enzyme to lignin. Delignification processes are too expensive, complicated and, for at least these reasons, are not efficient ways of addressing the problems. Free lignin (separated from lignocelluloses) can be removed by further washing, but washing is an environmental concern as it uses too much water. Bound lignin (unseparated lignin on solids) can be blocked using surfactants or metals, but the levels required are too expensive.
Accordingly, the art would appreciate (i) a way of efficiently reducing the dosage of enzyme required to achieve a desired level of saccharification of a polysaccharide; (ii) a process that is environmentally friendly in that it does not require an abundance of water; and, (iii) a process that is economically efficient in that it doesn't require an expensive process step or a costly addition of chemicals to achieve the desired level of saccharification. It should be appreciated that the teachings provided herein are generally directed to a system for reducing non-specific binding of an enzyme to lignin to enhance an enzymatic processing of a lignocellulosic material and, as such, the benefits provided by the teachings herein may be utilized in any biorefinery process that uses an enzyme to convert a lignocellulosic material to a product.